Methanol and proton transport through chitosan‐phosphotungstic acid membranes for direct methanol fuel cell. (10th August 2020)

• Record Type: Journal Article
• Authors: Zaffora, Andrea; Di Franco, Francesco; Gradino, Emanuele; Santamaria, Monica
• Is Part Of: International journal of energy research. Volume 44:Number 14(2020)
• Page Start: 11550
• Page End: 11563
• Publication Date: 2020-08-10
• Subjects: chitosan -- direct methanol fuel cells -- methanol permeability -- phosphotungstic acid -- proton conductivity; Power resources -- Periodicals; Power (Mechanics) -- Periodicals; Power resources -- Research -- Periodicals; 621.042
• DOI: 10.1002/er.5777
• Languages: English
• ISSNs: 0363-907X

Abstract

Summary: Composite chitosan‐phosphotungstic acid membranes were synthesized by ionotropic gelation. Their liquid uptake is higher for thin membranes (23 ± 2 μm), while it is lower (~70%) for thicker membranes (50‐70 μm). Polarization curves recorded using single module fuel cell at 70°C allowed to estimate a peak power density of 60 mW cm −2 by using 1 M as methanol and low Pt and Pt/Ru loadings (0.5 and 3 mg cm −2 ) at the cathode and at the anode, respectively. Electrochemical impedance spectroscopy was used to estimate the membrane conductivity and to model the electrochemical behavior of methanol electrooxidation inside the fuel cell revealing a two‐step mechanism mainly responsible of overall kinetic losses. Transport of methanol inside the membrane was studied by potentiostatic measurements, allowing to estimate a methanol diffusivity of 3.6 × 10 −6 cm 2 s −1 . Abstract : Chitosan‐phosphotungstic acid composite membranes were prepared by ionotropic gelation and were applied as proton exchange membranes in a methanol‐fed fuel cell. A power density peak of 60 mW cm −2 was reached using low methanol concentration and low catalyst loadings at the electrodes. Insights about electrooxidation of methanol and its transport through the membrane during fuel cell operation were gained.